Evaluation of two food grade proliposomes to encapsulate an extract of a commercial enzyme preparation by microfluidization.

The entrapment by microfluidization of a commercial enzyme extract (Debitrase DBP20) in liposomes using two food grade proliposome (C and S) preparations was studied. Liposomes obtained at a low microfluidization pressure (4000 psi) were distributed in a bimodal population of small (30-40 nm) and large vesicles (300-700 nm). The composition of the proliposome influenced entrapment efficiency and the repartition of the enzyme between the core and the surface of the liposome. More enzyme was associated with the liposomal surface and greater entrapment efficiencies (64%) were obtained for liposomes with the highest negative zeta potential (proliposome C). Increasing microfluidization pressure and increasing the number of passes through the microfluidizer resulted in losses in entrapment efficiency and enzyme activity, due to decreasing liposome size and enzyme denaturation. Entrapment efficiency was not influenced by external pH and enzyme activity was not adversely affected over storage for 18 days under the conditions evaluated.